With the advent of the advanced intelligent network (AIN), it has become possible to rapidly design and introduce many new enhanced telecommunications services that provide added flexibility and convenience in how we use our telephone equipment.
The advanced intelligent network typically includes switches or service switching points (SSPs) coupled to signal transfer points (STPs), which are in turn coupled to service control points (SCPs). The interconnections between service switching points and service control points employ the signaling system number 7 or SS7 protocol for sending query messages associated with the execution of services. The service control points executes service logic programs which define the services and further store and maintain databases that have data associated with the services. The service control points are further coupled to a service management system (SMS), which supports the operations, administrations, management, and provisioning (OAM&P) needs of the network. The advanced intelligent network further includes intelligent peripherals, which are coupled to service switching points and the service management system, and provide pre-recorded voice announcements, voice synthesis, and other functionalities that generally facilitate interaction with service subscribers and customers. The connection between the service management system and other network nodes is typically via X.25 links. In the advanced intelligent network, telecommunications services are typically defined in a service creation environment (SCE) node by the service provider and then relayed to the service management system, which disseminates the service logic programs to the rest of the network for execution.
The International Telecommunications Union (ITU) and other standard setting bodies have promulgated recommendations and requirements for advanced intelligent network services. One service is the universal personal telecommunications service, which basically allows a service subscriber to be reached with one telephone number, regardless of his/her present location. However, these standards do not spell out how this service is to be implemented and the specific service features that support this service.